1. Field
The present invention relates to a system and method for detecting unwanted wrapping of a strip of material around at least one feed roller. Specifically, the present invention relates to a fiber optic sensor for detecting if any of a plurality of strips of composite fiber tow are beginning to wrap around a feed roller within a composite fiber tow placement machine.
2. Related Art
Composite fiber tow or tape is used in the manufacture of composite parts, such as various aircraft components. Composite fiber tow may be an elongated strip of composite material, and a plurality of strips of composite fiber tow may be fed through a composite fiber tow placement machine having at least one compaction head or compaction roller configured for compacting the composite fiber tow onto a surface of a desired size and shape to form the composite part. However, in various tow placement machines, an error or malfunction called “tow wrap” may occasionally occur, in which one of the strips of composite fiber tow gets caught in a feed roller inside of the tow placement machine, and begins to wrap around the feed roller. Since the purpose of the feed roller is to urge the composite fiber tow forward, “tow wrap” creates an undesirable situation in which the tow is not urged forward and may even become jammed within the tow placement machine as the composite fiber tow attempts to wrap around the feed roller.
Typically, a “tow wrap” may go undetected until an operator visually notices that one or more of the strips of composite fiber tow have not exited the tow placement machine, or until the tow placement machine becomes jammed. If the tow placement machine becomes jammed due to “tow wrap”, internal damage may occur within the tow placement machine. Additionally, it can be difficult to remove the composite fiber tow from the feed roller when it becomes jammed. Therefore “tow wrap” may cause undesired repair costs and downtime.
Accordingly, there is a need for a method of detecting “tow wrap” within composite fiber tow placement machines that overcomes the limitations of the prior art.